On 05/28/2013 07:52 PM, Fabien COELHO wrote: > > However I'm not sure that pg_stat_replication currently has the > necessary information on either side to measure the lag (in time > transactions, but how do I know when a transaction was committed? or > number of transactions?).
The BDR codebase now has a handy function to report when a transaction was committed, pg_get_transaction_committime(xid) . It also adds pg_xlog_wait_remote_apply and pg_xlog_wait_remote_receive that can be used with pg_current_xlog_location() to wait until one or all replicas have caught up, or with LSNs from pg_stat_replication to (say) wait until all replicas have caught up with the most up-to-date one. I don't think these depend on anything BDR-specific, though Andres or Álvaro would be able to say for sure. Take a look in: git://git.postgresql.org/git/users/andresfreund/postgres.git on the 'bdr' branch. Be aware that it is rebased regularly, though the '0.4' tag applied earlier today will remain constant and contains the functions of interest. I hope this helps. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
